Decobalting of aldehydes in the oxo process



April 23, y1957 J. K. GOERNER ET Ax. 2,790,007

DECOBALTING OF' ALDEHYDES IN THE OXO PROCESS Fild Nov. 19, 1954 HOLOVB .LX 3

` INVENTOR h .Josp ahl Goe J 0f Foser'ozze BY ATTORNEY "other ,Soli/ents, auch as.. ."benZenS.; .Xylenen ethyl l ionmene and commercial *aliphatic hydrocar-bo` United States Patent lice DECOBALTING OF ALDEHYDES IN THEOXf n PRQCESS Joseph Kofahl'Goerner. and james Foster Bone, Austin,

New York,-N. Y., a corporation of Delavvarejk l I Application Novembar 19, .1.954, Serial No..-41'0,901 1o claims'. (cls.y `26o- 604).

Tex., assignors to Jeterson'Chemical Company, Inc-1 This invention relates to the production of oxygenated organic compounds by the `sro-called oxo process, and" more particularlyto the recovery from thev reaction mixture produced in the carbony-lat-ion .step of 'the desired taldehydeproduot and the carbQny-lation Catalyst, the latter in a res-usable form.

In the carbonylation of olelins Iwith synthesisfgas con sistinguof. carbon monoxide andhydrogen, in thepresence of a cobalt` catalyst and an inert Water-infirniscible Solvent, such as toluene, a carbonylation mixture lco,rrsistgingoh'iey of the solvent, aldehyde land cobalt catalyst isrproduced.

The mechanism oft-he catalysis is not .fullyylgnown It is believed that the active catalyst is Ia labile, cobalt com Pound which, may be produced. in the reaction zone vfrom Cabalt Or 011e. 0f f1.1@ Gehalt arbnyls which. are. invariably' Prescnfurida the. temnerature and. pressure conditions 4@,rlpli'd in. Garry-.ina yout thearbonrlatien. Stepv It lhas been proposed to recover the' cobalt catalyst and the alshydeq-fram Slwh` reaction mixtures-bmahljecting them'vto a thermal `or acid decobalting, followed by Subsequent distillation t9. recover the product... procedures involve decomposition ofalljol'the, the. reaction. mixture, followed by .a regalar Catall/Stand areiherefw irlvfvflved.` and costln o 'It has @sabran Proposed. tQ Subject the, carb'onylasynthesisfgastin the p'resenceof .an vinert solventlanda s 2,790,007 Pafentedlnpi. 123, 1957 Thesynthesis'ga's employedlm'ay contain hydrogen and caribonfmonoxideina ratio of ltov 1, l"although"m'ixtl'ires containing hydrogen and carbon monoxide' in ratios varyilrig'fromr 0.5tov 3.0 'may b'e used. f i i IThefcarbonylation'reaction is eXothe'rrni'c `and is de'- .sirably' 'carried' outiwhi-le' 'cooling 'the *reaction mixture maintaining a temperature of from 300 to36`0k F., preferably1 aboutl340 The'reaction isc'arried' out under aip'res'surefofv from 500y`to 5,000 p'. s. i. g;, preferably `about3,000 to 3,'500`p. s. i. g.

The- 'catalyst employedv inthe reaction is a cobalt 'conr- -pound produced by reacting, forexa'mple, c'baltacetate", cobalt carbonate, hydroxide, or *oXideg inthep'r'esenc of al suitable solvent" vfor thecobalt"catalyst,vv such, foreiampl, as propanol, with rsynth'esisfgas at elevatedtem peratures and pressures correspondingto those employed in the carbonyl-lation step.` l`he-cobalt catalyst'could; foi' example, be produced in the'carbonylator by introducing affcobalt salt, `such as cobalt acetate or other cobalt 4com Vil() poundflintoithe carbonylator Where it reacts with the synthesis gas to produce the catalyst.I The catalyst is believed'tobe chiefly cobalt hyd-rocarbonyl,v which is appreciably water-soluble;` However, upon standing in the absence of* hydrogen, cobalt"v hydrlocarbonyl. or' other water-soluble cobalt carbonyl compoundspres'ent.readily changeitocobalt carbonyls 'whichl are'- wat'ep'r-insolugble. y

The?*carbonylation` reaction Ymixture'f'is fedk fr'tn'n'tln'e carbonylator through'a cooler j-wh'ereitv cooled .t'oifrom 40 to; 100 Fi, preferably about 100"V PL, andthen 3 0 introduced into a high-pressure separator where'- some Aof the lunreacted ygas is separated fromf-the :liquid in the reaction mixturef Desirably, the high-pressurefvsepa'rator isV maintained .at ya pressure of about 10 to 50p. s. i. g. below-the pressure in the carbonylator.

35 From the `high-pressure separator the reactionV mixture `passes int-'0 va low-pressure separator maintained at a pressure 'of"frorn 5 to 2001. s. i. g., :Where separation of the liquid rfrom the gasI takes place'; The' gas consisting l chieyv-of unreacted carbonr'monoxide, hydrogen and eth- Iane or` propane is. separated from lthe liquid `and 'isin 'part recyoledrt-o the process- Iby... admixture with thefsyn- .thesis "gasfed tothe carbonylator and in part purged from 'th process.V l f .f v f .The liquid'productv from the 1owpressnre separator l Y consistinglchieily of aldehyde, solvent and. cobalt catajllystfis, then1 subjectedl .to Iaging..tofconvert- -the'- watersoluble.. cobalt compounds, chiey.- beliesv'edl -tobe cobalt hydrocarbonyh; to water-insoluble. cobalt compounds, chiefly jcobalt carbonyls. Thismaylbe :accomplished by passing' the liquidproductinto .a sofcalledfsoakingfta Whereit is. permitted -t-o Iremainatvfrom.4,0"yto 100 F. forlongenough for such, oonversionto take-place,or by Y havingfthedlovv path .throughiwhichqthe liquid flowsto 'the1 extractorgof sutil-cient extent -toperrnitthis conversion vtojttakeplace.f lngeneral,- aging Yof 'llthealiquid for about cobalt catalyst, after con-versionof thercobalt'cat'alyst to l the'aldehyde and araiiiate Ycontaiifiingthe so entari'd the. Cobalt Catalyst- This.V .extract @can bel distilled top10# i may be used.

l 7o trombi. temperaturen@arsssura malos/ed 11.1: the fp roess a f 1` 'to 5 hours, i. e., providing .a'iiow path 'or soaking-0r storage .zone of a capa-city` suchothatf-each" particleN of liquidpi-oduot is f .aged for a-period of-'ir'om-I 1l to 5 hours afterf. leaving the low-pressure r`.separatorz and, be- .fore entering theextractor, will suice to insurethat-the desired. conversion. tof-r water-solublefcobtalt compounds j g, )i l .in .f the; absence of f substantial amounts `of ghyf drogen. Y

.preferably carried j out continuously v in any 'fsuitable'fextraction',tower,` such.--ras .fa spray,- .towen-packed-tower,

iScheibel-gcolumn, etc. Either.thee-carbonylation liquid the. Mater.: phase may be t:oritinil'ouslI y Itl islpreferred,

lion/even to. have the water phase continuous. The ex- ,iwaterinsoluble:cobaltcompounds. has l'taken place.

traction is preferably carried out at atmospheric temperatures, although temperatures up to 200 F. may be used, if desired. It is carried out under a small pressure of carbon monoxide, preferably of from 5 to 100 p. s. i. g. and preferably in the absence of substantial amounts of hydrogen, to prevent decomposition of the cobalt carbonyl compounds. When operating in Athe higher portion of this temperature range, carbon monoxidepressures in the higher portion 'of the aforementioned pressure range should be employed to minimize decomposition of cobalt carbonyls to cobalt metal.

From the extractor the aqueous extract containing extracted propionaldehyde is subjected to fractionaldistillation to recover the aldehyde overhead as a s ubstanvtially pure product. Water containing .trace amounts of ycobalt compounds is removed from the bottom of the column and after cooling may be used in the` extraction step. Most of Ithe cobalt in the water-extract phase appearsrto be present as the formate and proprionate- (when f ethylene is being carbonylated) or the formate and'butyrate (when propylene is being carbonylated). These co balt values may be recovered by concentrating aportion .of the Water streamV and injecting the resulting concen- `trated cobalt solution into the -carbonylator ,as part of the cobalt make-up. n

The rainate from the extractor containing the cobalt ,catalyst is recycled to the carbonylator, v A

The accompanying drawing shows a preferred arrangement of the equipment, illustrated diagrammatically, for

practicing the process of this invention. The legends on this drawing arev self-explanatory. `In view ofA these legends and the above description of the process it is believed that further description lof the drawing is unnecessary. Y

The following example of the production of proprionvaldehyde from ethylene and synthesis gas in the presence of a cobalt catalyst and toluene diluent is given for pur- 'poses of illustration only. It will be understood that the invention is not limited to this example, but includes the production of butyraldehyde or mixtures of propionaldehyde and butyraldehyde from propylene and mixtures of ethyleneand propylene respectively:

' Example The carbonylator is main-tained at a temperature of l340" F. and a pressure of 3,200 p. sl i. g. As ythe reaction vis ex-othermic the temperature of 340 F. is maintained by circulating a suitable cooling medium through the jacket of the carbonylator. Ethylene preheated to 340 'R at a pressure of 3,200'p. s. i. g., and a mixture of 'synthesis gas (CO:H2=l:l -on a molar basis), and toluene at a pressureof 3,200 p. s. i. g.r are fed to' the carb-onylator. Make-up cobalt carbonyl catalyst and'cobalt carbonyl from the extractor are introduced into the ca-rbonylator along with the synthesis gas and the toluene diluent, as indicated in the accompanying drawing. In the carbonylator the cobalt carbonyl 'is converted to watersoluble cobalt compounds, chiey cobalt hydrocarbonyl. The carbonylation is carried out as .a homogeneous liquid phase reaction catalyzed by -the dissolved 'cobalt hydro- 'carbonyL i The ethylene is supplied continuously at therateY of 49 s. c, f. h: (standard cubicY feet per hour; by standard, of course, is meant at 1 atmosphere pressure and 60 F.)

and the synthesis gas at the rate of 135 s. c. f. h. The

solution of cobalt catalyst from the extractor is recycled to .the carbonylator at the rate of 22.2 lbs/hr.` 'Makeup catalyst solution containing approximately 3% cobalt carbonyl is supplied at'the rate of 0.15 lb./hr. The' reaction 4 of 26.3 lbs/hr. The liquid from the lowpressure separator, after aging for 4 hours thus converting most watersoluble cobalt compounds to water-insoluble compounds and at :a temperature `of 100 F., is passed continuously into the extractor at -a rate of 26.3 lbs/hr. lRatiinate conytaining cobalt catalyst is withdrawn at the rate of 22.2 lbs/hr. and returned to the carb'onylator, las hereinabove described. The extract -is withdrawn from the extractor at a ra-te of 133.5 lbs/hr. and passed into a fractionating column Where it is distilled.

Propionaldehyde containing about 1.9% water by weight is taken off overhead. The 'bottoms stream con sisting of practically pure wateris returned to the extraction column for re-use.

llt will be noted that the present invention provides a process for treating carbonylation mixtures, which results in the direct recovery of the cobalt catalyst in reusable form. The process of this invention can be carried out simply and economically. It does not require the carefully controlled conditions of temperature and pressure to prevent decomposition of the cobalt catalyst and product loss as in the case of certain prior known procedures, such, for example, as the flash distillation procedure heretofore suggested for treatment of carbonylation mixtures, to recover the cobalt catalyst and the aldehyde.

It is to be understood that this invention is not restricted to the present disclosure otherwise than as defined by the appended claims.

What is claimed is:

1. In a process of producing an aldehyde of the group consisting of propionaldehyde rand butyraldehyde by reacting an olefin from the group consisting of ethylene and propylene with synthesis gas in the presence of a water-soluble cobalt catalyst, the improvement which comprises aging the reaction mixture until said watersoluble cobalt catalyst is substantially converted toV waterinsoluble cobalt compounds, and extracting the reaction mixture with water to produce an aqueous mixture containing the aldehyde and a raffinate containing the water insoluble cobalt compounds.

2. A process of producing an aldehyde of thegroup consisting of propionaldehyde and butyraldehyde by reacting an olefin from the group consisting of ethylene and propylenewith ,carbon monoxide and hydrogen and in the presence of Aa cobalt catalyst and an inert solvent for the cobalt catalyst to produce a reaction mixture containing said aldehyde, cobalt catalyst, solvent and unreacted carbon monoxide and hydrogen under elevated pressures, which process comprises reducing the pressure apressure of carbon monoxide of from 5 to 100 p. s. i. g.

mix-ture is'withdrawn from -the carbonylat'or at the rate of Y 26.3 lbs/hr. at a temperature of 340 F., cooled to 100 FV-passed intothe high-pressure separator'at a pres- `sure of 3,150 p. s. i. '.g, and then into theV low-pressure separator where `the pressure is reduced toV 80p.l s. i. g.

From the low-pressure separator lthe gas is withdrawn at the rate of 22 s. c.v f. h. and the liquid atthe'rate 4. AV process of producing propionaldehyde by reactfing ethylene with carbon monoxide and hydrogen in t-hc presence of a cobalt catalyst and an inert solvent for the F cobalt catalyst to produce a reactionmixture 'containing propionaldehyde, cobalt catalyst,'said solvent and un- "reacted carbon' monoxide andhydrogen under elevated pressures, which process comprises reducing the pressure on said reaction mixture, separating the liquid' from Vthe 'carbon vmonoxide and hydrogen, aging the separated jliquid fora period sufficient .to convert water-soluble cobaltcompounds to water-insoluble cobalt compounds, "extracting the aged liquid with water to form an aqueous solution of the propionaldehyde and a ranate contain- 'ing water-insolublecobalt compounds vand solvent, and

utilizing the raffinate to supply at least -a portion of the cobalt catalyst and solvent employed in the reaction.

5. The process as .dened in claim 4, in which the extraction of said liquid with water is carried out under a pressure of carbon monoxide of from 5 to 100 p. s. i. g.

6. A process according to claim 1 in which said aging is conducted in the absence of added water.

7. The process of treating a carbonylation reaction mixture comprising an aldehyde, Ifrom the group consisting of propionaldehyde and butyraldehyde, a watersoluble cobalt catalyst and an inert solvent, which comprises aging said reaction mixture at .a temperature of about 40 to 100 F. until said Water-soluble cobalt catalyst is substantially converted to a water-insoluble cobalt catalyst, and extracting said mixture with water to produce an aqueous mixture containing said aldehyde and the rainate containing said inert solvent and said water insoluble cobalt catalyst dissolved therein.

8. A process according to claim 7 in which said aging is conducted in theabsence of added water.

9. A process `according to claim 7 in which said aging is conducted under about 5 to 100 p. s. i. g. of carbon monoxide.

10. A process according to claim 7 in which said aging is conducted `for a period of about 1 to 5 hours.

References Cited in the le of this patent UNITED STATES PATENTS 

1. IN A PROCESS OF PRODUCING AN ALDEHYDE OF THE GROUP CONSISTING OF PROPIONALDEHYDE AND BUTYRALDEHYDE BY REACTING AN OLEFIN FROM THE GROUP CONSISTING OF ETHYLENE AND PROPYLENE WITH SYNTHESIS GAS IN THE PRESENCE OF A WATER-SOLUBLE COBALT CALALYST, THE IMPROVEMENT WHICH COMPRISES AGING THE REACTION MIXTURE UNTIL SAID WATERSOLUBLE COBALT CATALYST IS SUBSTANTIALLY CONVERTED TO WATERINSOLUBLE COBALT COMPOUNDS, AND EXTRACTING THE REACTION MIXTURE WITH WATER TO PRODUCE AN AQUEOUS MIXTURE CONTAINING THE ALDEHYDE AND A RAFFINATE CONTAINING THE WATER INSOLUBLE COBALT COMPOUNDS. 